Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

Two bugfixes in XFS for 3.3: one fix passes KMEM_SLEEP to kmem_realloc
instead of 0, and the other resolves a possible deadlock in xfs quotas.

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: use a normal shrinker for the dquot freelist
  xfs: pass KM_SLEEP flag to kmem_realloc() in xlog_recover_add_to_cnt_trans()

7 files changed, 142 insertions, 283 deletions

diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h
index 292eff198030..ab7c53fe346e 100644
--- a/fs/xfs/kmem.h
+++ b/fs/xfs/kmem.h
@@ -110,10 +110,4 @@ kmem_zone_destroy(kmem_zone_t *zone)
 extern void *kmem_zone_alloc(kmem_zone_t *, unsigned int __nocast);
 extern void *kmem_zone_zalloc(kmem_zone_t *, unsigned int __nocast);
 
-static inline int
-kmem_shake_allow(gfp_t gfp_mask)
-{
-        return ((gfp_mask & __GFP_WAIT) && (gfp_mask & __GFP_FS));
-}
-
 #endif /* __XFS_SUPPORT_KMEM_H__ */
diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index b4ff40b5f918..cbcb7bea38e2 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -63,82 +63,6 @@ int xfs_dqerror_mod = 33;
 static struct lock_class_key xfs_dquot_other_class;
 
 /*
- * Allocate and initialize a dquot. We don't always allocate fresh memory;
- * we try to reclaim a free dquot if the number of incore dquots are above
- * a threshold.
- * The only field inside the core that gets initialized at this point
- * is the d_id field. The idea is to fill in the entire q_core
- * when we read in the on disk dquot.
- */
-STATIC xfs_dquot_t *
-xfs_qm_dqinit(
-        xfs_mount_t  *mp,
-        xfs_dqid_t   id,
-        uint         type)
-{
-        xfs_dquot_t     *dqp;
-        boolean_t       brandnewdquot;
-
-        brandnewdquot = xfs_qm_dqalloc_incore(&dqp);
-        dqp->dq_flags = type;
-        dqp->q_core.d_id = cpu_to_be32(id);
-        dqp->q_mount = mp;
-
-        /*
-         * No need to re-initialize these if this is a reclaimed dquot.
-         */
-        if (brandnewdquot) {
-                INIT_LIST_HEAD(&dqp->q_freelist);
-                mutex_init(&dqp->q_qlock);
-                init_waitqueue_head(&dqp->q_pinwait);
-
-                /*
-                 * Because we want to use a counting completion, complete
-                 * the flush completion once to allow a single access to
-                 * the flush completion without blocking.
-                 */
-                init_completion(&dqp->q_flush);
-                complete(&dqp->q_flush);
-
-                trace_xfs_dqinit(dqp);
-        } else {
-                /*
-                 * Only the q_core portion was zeroed in dqreclaim_one().
-                 * So, we need to reset others.
-                 */
-                dqp->q_nrefs = 0;
-                dqp->q_blkno = 0;
-                INIT_LIST_HEAD(&dqp->q_mplist);
-                INIT_LIST_HEAD(&dqp->q_hashlist);
-                dqp->q_bufoffset = 0;
-                dqp->q_fileoffset = 0;
-                dqp->q_transp = NULL;
-                dqp->q_gdquot = NULL;
-                dqp->q_res_bcount = 0;
-                dqp->q_res_icount = 0;
-                dqp->q_res_rtbcount = 0;
-                atomic_set(&dqp->q_pincount, 0);
-                dqp->q_hash = NULL;
-                ASSERT(list_empty(&dqp->q_freelist));
-
-                trace_xfs_dqreuse(dqp);
-        }
-
-        /*
-         * In either case we need to make sure group quotas have a different
-         * lock class than user quotas, to make sure lockdep knows we can
-         * locks of one of each at the same time.
-         */
-        if (!(type & XFS_DQ_USER))
-                lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
-
-        /*
-         * log item gets initialized later
-         */
-        return (dqp);
-}
-
-/*
  * This is called to free all the memory associated with a dquot
  */
 void
@@ -567,7 +491,32 @@ xfs_qm_dqread(
         int                     error;
         int                     cancelflags = 0;
 
-        dqp = xfs_qm_dqinit(mp, id, type);
+
+        dqp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
+
+        dqp->dq_flags = type;
+        dqp->q_core.d_id = cpu_to_be32(id);
+        dqp->q_mount = mp;
+        INIT_LIST_HEAD(&dqp->q_freelist);
+        mutex_init(&dqp->q_qlock);
+        init_waitqueue_head(&dqp->q_pinwait);
+
+        /*
+         * Because we want to use a counting completion, complete
+         * the flush completion once to allow a single access to
+         * the flush completion without blocking.
+         */
+        init_completion(&dqp->q_flush);
+        complete(&dqp->q_flush);
+
+        /*
+         * Make sure group quotas have a different lock class than user
+         * quotas.
+         */
+        if (!(type & XFS_DQ_USER))
+                lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
+
+        atomic_inc(&xfs_Gqm->qm_totaldquots);
 
         trace_xfs_dqread(dqp);
 
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 541a508adea1..15ff5392fb65 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -1489,7 +1489,7 @@ xlog_recover_add_to_cont_trans(
         old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
         old_len = item->ri_buf[item->ri_cnt-1].i_len;
 
-        ptr = kmem_realloc(old_ptr, len+old_len, old_len, 0u);
+        ptr = kmem_realloc(old_ptr, len+old_len, old_len, KM_SLEEP);
         memcpy(&ptr[old_len], dp, len); /* d, s, l */
         item->ri_buf[item->ri_cnt-1].i_len += len;
         item->ri_buf[item->ri_cnt-1].i_addr = ptr;
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 671f37eae1c7..c436def733bf 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -50,7 +50,6 @@
  */
 struct mutex    xfs_Gqm_lock;
 struct xfs_qm   *xfs_Gqm;
-uint            ndquot;
 
 kmem_zone_t     *qm_dqzone;
 kmem_zone_t     *qm_dqtrxzone;
@@ -93,7 +92,6 @@ xfs_Gqm_init(void)
                 goto out_free_udqhash;
 
         hsize /= sizeof(xfs_dqhash_t);
-        ndquot = hsize << 8;
 
         xqm = kmem_zalloc(sizeof(xfs_qm_t), KM_SLEEP);
         xqm->qm_dqhashmask = hsize - 1;
@@ -137,7 +135,6 @@ xfs_Gqm_init(void)
                 xqm->qm_dqtrxzone = qm_dqtrxzone;
 
         atomic_set(&xqm->qm_totaldquots, 0);
-        xqm->qm_dqfree_ratio = XFS_QM_DQFREE_RATIO;
         xqm->qm_nrefs = 0;
         return xqm;
 
@@ -1600,216 +1597,150 @@ xfs_qm_init_quotainos(
         return 0;
 }
 
+STATIC void
+xfs_qm_dqfree_one(
+        struct xfs_dquot        *dqp)
+{
+        struct xfs_mount        *mp = dqp->q_mount;
+        struct xfs_quotainfo    *qi = mp->m_quotainfo;
 
+        mutex_lock(&dqp->q_hash->qh_lock);
+        list_del_init(&dqp->q_hashlist);
+        dqp->q_hash->qh_version++;
+        mutex_unlock(&dqp->q_hash->qh_lock);
 
-/*
- * Pop the least recently used dquot off the freelist and recycle it.
- */
-STATIC struct xfs_dquot *
-xfs_qm_dqreclaim_one(void)
+        mutex_lock(&qi->qi_dqlist_lock);
+        list_del_init(&dqp->q_mplist);
+        qi->qi_dquots--;
+        qi->qi_dqreclaims++;
+        mutex_unlock(&qi->qi_dqlist_lock);
+
+        xfs_qm_dqdestroy(dqp);
+}
+
+STATIC void
+xfs_qm_dqreclaim_one(
+        struct xfs_dquot        *dqp,
+        struct list_head        *dispose_list)
 {
-        struct xfs_dquot        *dqp;
-        int                     restarts = 0;
+        struct xfs_mount        *mp = dqp->q_mount;
+        int                     error;
 
-        mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
-restart:
-        list_for_each_entry(dqp, &xfs_Gqm->qm_dqfrlist, q_freelist) {
-                struct xfs_mount *mp = dqp->q_mount;
+        if (!xfs_dqlock_nowait(dqp))
+                goto out_busy;
 
-                if (!xfs_dqlock_nowait(dqp))
-                        continue;
+        /*
+         * This dquot has acquired a reference in the meantime remove it from
+         * the freelist and try again.
+         */
+        if (dqp->q_nrefs) {
+                xfs_dqunlock(dqp);
 
-                /*
-                 * This dquot has already been grabbed by dqlookup.
-                 * Remove it from the freelist and try again.
-                 */
-                if (dqp->q_nrefs) {
-                        trace_xfs_dqreclaim_want(dqp);
-                        XQM_STATS_INC(xqmstats.xs_qm_dqwants);
-
-                        list_del_init(&dqp->q_freelist);
-                        xfs_Gqm->qm_dqfrlist_cnt--;
-                        restarts++;
-                        goto dqunlock;
-                }
+                trace_xfs_dqreclaim_want(dqp);
+                XQM_STATS_INC(xqmstats.xs_qm_dqwants);
 
-                ASSERT(dqp->q_hash);
-                ASSERT(!list_empty(&dqp->q_mplist));
+                list_del_init(&dqp->q_freelist);
+                xfs_Gqm->qm_dqfrlist_cnt--;
+                return;
+        }
 
-                /*
-                 * Try to grab the flush lock. If this dquot is in the process
-                 * of getting flushed to disk, we don't want to reclaim it.
-                 */
-                if (!xfs_dqflock_nowait(dqp))
-                        goto dqunlock;
+        ASSERT(dqp->q_hash);
+        ASSERT(!list_empty(&dqp->q_mplist));
 
-                /*
-                 * We have the flush lock so we know that this is not in the
-                 * process of being flushed. So, if this is dirty, flush it
-                 * DELWRI so that we don't get a freelist infested with
-                 * dirty dquots.
-                 */
-                if (XFS_DQ_IS_DIRTY(dqp)) {
-                        int     error;
+        /*
+         * Try to grab the flush lock. If this dquot is in the process of
+         * getting flushed to disk, we don't want to reclaim it.
+         */
+        if (!xfs_dqflock_nowait(dqp))
+                goto out_busy;
 
-                        trace_xfs_dqreclaim_dirty(dqp);
+        /*
+         * We have the flush lock so we know that this is not in the
+         * process of being flushed. So, if this is dirty, flush it
+         * DELWRI so that we don't get a freelist infested with
+         * dirty dquots.
+         */
+        if (XFS_DQ_IS_DIRTY(dqp)) {
+                trace_xfs_dqreclaim_dirty(dqp);
 
-                        /*
-                         * We flush it delayed write, so don't bother
-                         * releasing the freelist lock.
-                         */
-                        error = xfs_qm_dqflush(dqp, SYNC_TRYLOCK);
-                        if (error) {
-                                xfs_warn(mp, "%s: dquot %p flush failed",
-                                        __func__, dqp);
-                        }
-                        goto dqunlock;
+                /*
+                 * We flush it delayed write, so don't bother releasing the
+                 * freelist lock.
+                 */
+                error = xfs_qm_dqflush(dqp, 0);
+                if (error) {
+                        xfs_warn(mp, "%s: dquot %p flush failed",
+                                 __func__, dqp);
                 }
-                xfs_dqfunlock(dqp);
 
                 /*
-                 * Prevent lookup now that we are going to reclaim the dquot.
-                 * Once XFS_DQ_FREEING is set lookup won't touch the dquot,
-                 * thus we can drop the lock now.
+                 * Give the dquot another try on the freelist, as the
+                 * flushing will take some time.
                  */
-                dqp->dq_flags |= XFS_DQ_FREEING;
-                xfs_dqunlock(dqp);
-
-                mutex_lock(&dqp->q_hash->qh_lock);
-                list_del_init(&dqp->q_hashlist);
-                dqp->q_hash->qh_version++;
-                mutex_unlock(&dqp->q_hash->qh_lock);
-
-                mutex_lock(&mp->m_quotainfo->qi_dqlist_lock);
-                list_del_init(&dqp->q_mplist);
-                mp->m_quotainfo->qi_dquots--;
-                mp->m_quotainfo->qi_dqreclaims++;
-                mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
+                goto out_busy;
+        }
+        xfs_dqfunlock(dqp);
 
-                ASSERT(dqp->q_nrefs == 0);
-                list_del_init(&dqp->q_freelist);
-                xfs_Gqm->qm_dqfrlist_cnt--;
+        /*
+         * Prevent lookups now that we are past the point of no return.
+         */
+        dqp->dq_flags |= XFS_DQ_FREEING;
+        xfs_dqunlock(dqp);
 
-                mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
-                return dqp;
-dqunlock:
-                xfs_dqunlock(dqp);
-                if (restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
-                        break;
-                goto restart;
-        }
+        ASSERT(dqp->q_nrefs == 0);
+        list_move_tail(&dqp->q_freelist, dispose_list);
+        xfs_Gqm->qm_dqfrlist_cnt--;
 
-        mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
-        return NULL;
-}
+        trace_xfs_dqreclaim_done(dqp);
+        XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
+        return;
 
-/*
- * Traverse the freelist of dquots and attempt to reclaim a maximum of
- * 'howmany' dquots. This operation races with dqlookup(), and attempts to
- * favor the lookup function ...
- */
-STATIC int
-xfs_qm_shake_freelist(
-        int     howmany)
-{
-        int             nreclaimed = 0;
-        xfs_dquot_t     *dqp;
+out_busy:
+        xfs_dqunlock(dqp);
 
-        if (howmany <= 0)
-                return 0;
+        /*
+         * Move the dquot to the tail of the list so that we don't spin on it.
+         */
+        list_move_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
 
-        while (nreclaimed < howmany) {
-                dqp = xfs_qm_dqreclaim_one();
-                if (!dqp)
-                        return nreclaimed;
-                xfs_qm_dqdestroy(dqp);
-                nreclaimed++;
-        }
-        return nreclaimed;
+        trace_xfs_dqreclaim_busy(dqp);
+        XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
 }
 
-/*
- * The kmem_shake interface is invoked when memory is running low.
- */
-/* ARGSUSED */
 STATIC int
 xfs_qm_shake(
-        struct shrinker *shrink,
-        struct shrink_control *sc)
+        struct shrinker         *shrink,
+        struct shrink_control   *sc)
 {
-        int     ndqused, nfree, n;
-        gfp_t gfp_mask = sc->gfp_mask;
-
-        if (!kmem_shake_allow(gfp_mask))
-                return 0;
-        if (!xfs_Gqm)
-                return 0;
-
-        nfree = xfs_Gqm->qm_dqfrlist_cnt; /* free dquots */
-        /* incore dquots in all f/s's */
-        ndqused = atomic_read(&xfs_Gqm->qm_totaldquots) - nfree;
-
-        ASSERT(ndqused >= 0);
+        int                     nr_to_scan = sc->nr_to_scan;
+        LIST_HEAD               (dispose_list);
+        struct xfs_dquot        *dqp;
 
-        if (nfree <= ndqused && nfree < ndquot)
+        if ((sc->gfp_mask & (__GFP_FS|__GFP_WAIT)) != (__GFP_FS|__GFP_WAIT))
                 return 0;
+        if (!nr_to_scan)
+                goto out;
 
-        ndqused *= xfs_Gqm->qm_dqfree_ratio;    /* target # of free dquots */
-        n = nfree - ndqused - ndquot;           /* # over target */
-
-        return xfs_qm_shake_freelist(MAX(nfree, n));
-}
-
-
-/*------------------------------------------------------------------*/
-
-/*
- * Return a new incore dquot. Depending on the number of
- * dquots in the system, we either allocate a new one on the kernel heap,
- * or reclaim a free one.
- * Return value is B_TRUE if we allocated a new dquot, B_FALSE if we managed
- * to reclaim an existing one from the freelist.
- */
-boolean_t
-xfs_qm_dqalloc_incore(
-        xfs_dquot_t **O_dqpp)
-{
-        xfs_dquot_t     *dqp;
-
-        /*
-         * Check against high water mark to see if we want to pop
-         * a nincompoop dquot off the freelist.
-         */
-        if (atomic_read(&xfs_Gqm->qm_totaldquots) >= ndquot) {
-                /*
-                 * Try to recycle a dquot from the freelist.
-                 */
-                if ((dqp = xfs_qm_dqreclaim_one())) {
-                        XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
-                        /*
-                         * Just zero the core here. The rest will get
-                         * reinitialized by caller. XXX we shouldn't even
-                         * do this zero ...
-                         */
-                        memset(&dqp->q_core, 0, sizeof(dqp->q_core));
-                        *O_dqpp = dqp;
-                        return B_FALSE;
-                }
-                XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
+        mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+        while (!list_empty(&xfs_Gqm->qm_dqfrlist)) {
+                if (nr_to_scan-- <= 0)
+                        break;
+                dqp = list_first_entry(&xfs_Gqm->qm_dqfrlist, struct xfs_dquot,
+                                       q_freelist);
+                xfs_qm_dqreclaim_one(dqp, &dispose_list);
         }
+        mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
 
-        /*
-         * Allocate a brand new dquot on the kernel heap and return it
-         * to the caller to initialize.
-         */
-        ASSERT(xfs_Gqm->qm_dqzone != NULL);
-        *O_dqpp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
-        atomic_inc(&xfs_Gqm->qm_totaldquots);
-
-        return B_TRUE;
+        while (!list_empty(&dispose_list)) {
+                dqp = list_first_entry(&dispose_list, struct xfs_dquot,
+                                       q_freelist);
+                list_del_init(&dqp->q_freelist);
+                xfs_qm_dqfree_one(dqp);
+        }
+out:
+        return (xfs_Gqm->qm_dqfrlist_cnt / 100) * sysctl_vfs_cache_pressure;
 }
 
-
 /*
  * Start a transaction and write the incore superblock changes to
  * disk. flags parameter indicates which fields have changed.
diff --git a/fs/xfs/xfs_qm.h b/fs/xfs/xfs_qm.h
index 9b4f3adefbc5..9a9b997e1a0a 100644
--- a/fs/xfs/xfs_qm.h
+++ b/fs/xfs/xfs_qm.h
@@ -26,24 +26,12 @@
 struct xfs_qm;
 struct xfs_inode;
 
-extern uint             ndquot;
 extern struct mutex     xfs_Gqm_lock;
 extern struct xfs_qm    *xfs_Gqm;
 extern kmem_zone_t      *qm_dqzone;
 extern kmem_zone_t      *qm_dqtrxzone;
 
 /*
- * Ditto, for xfs_qm_dqreclaim_one.
- */
-#define XFS_QM_RECLAIM_MAX_RESTARTS     4
-
-/*
- * Ideal ratio of free to in use dquots. Quota manager makes an attempt
- * to keep this balance.
- */
-#define XFS_QM_DQFREE_RATIO             2
-
-/*
  * Dquot hashtable constants/threshold values.
  */
 #define XFS_QM_HASHSIZE_LOW             (PAGE_SIZE / sizeof(xfs_dqhash_t))
@@ -74,7 +62,6 @@ typedef struct xfs_qm {
         int              qm_dqfrlist_cnt;
         atomic_t         qm_totaldquots; /* total incore dquots */
         uint             qm_nrefs;       /* file systems with quota on */
-        int              qm_dqfree_ratio;/* ratio of free to inuse dquots */
         kmem_zone_t     *qm_dqzone;      /* dquot mem-alloc zone */
         kmem_zone_t     *qm_dqtrxzone;   /* t_dqinfo of transactions */
 } xfs_qm_t;
@@ -143,7 +130,6 @@ extern int		xfs_qm_quotacheck(xfs_mount_t *);
 extern int              xfs_qm_write_sb_changes(xfs_mount_t *, __int64_t);
 
 /* dquot stuff */
-extern boolean_t        xfs_qm_dqalloc_incore(xfs_dquot_t **);
 extern int              xfs_qm_dqpurge_all(xfs_mount_t *, uint);
 extern void             xfs_qm_dqrele_all_inodes(xfs_mount_t *, uint);
 
diff --git a/fs/xfs/xfs_qm_stats.c b/fs/xfs/xfs_qm_stats.c
index 8671a0b32644..5729ba570877 100644
--- a/fs/xfs/xfs_qm_stats.c
+++ b/fs/xfs/xfs_qm_stats.c
@@ -42,9 +42,9 @@ static int xqm_proc_show(struct seq_file *m, void *v)
 {
         /* maximum; incore; ratio free to inuse; freelist */
         seq_printf(m, "%d\t%d\t%d\t%u\n",
-                        ndquot,
+                        0,
                         xfs_Gqm? atomic_read(&xfs_Gqm->qm_totaldquots) : 0,
-                        xfs_Gqm? xfs_Gqm->qm_dqfree_ratio : 0,
+                        0,
                         xfs_Gqm? xfs_Gqm->qm_dqfrlist_cnt : 0);
         return 0;
 }
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 6b6df5802e95..bb134a819930 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -733,11 +733,10 @@ DEFINE_EVENT(xfs_dquot_class, name, \
 DEFINE_DQUOT_EVENT(xfs_dqadjust);
 DEFINE_DQUOT_EVENT(xfs_dqreclaim_want);
 DEFINE_DQUOT_EVENT(xfs_dqreclaim_dirty);
-DEFINE_DQUOT_EVENT(xfs_dqreclaim_unlink);
+DEFINE_DQUOT_EVENT(xfs_dqreclaim_busy);
+DEFINE_DQUOT_EVENT(xfs_dqreclaim_done);
 DEFINE_DQUOT_EVENT(xfs_dqattach_found);
 DEFINE_DQUOT_EVENT(xfs_dqattach_get);
-DEFINE_DQUOT_EVENT(xfs_dqinit);
-DEFINE_DQUOT_EVENT(xfs_dqreuse);
 DEFINE_DQUOT_EVENT(xfs_dqalloc);
 DEFINE_DQUOT_EVENT(xfs_dqtobp_read);
 DEFINE_DQUOT_EVENT(xfs_dqread);